A leading Hispanic Republican in Texas says he has decided to vote for Democratic presidential nominee Hillary Clinton.

Lionel Sosa, a veteran ad maker from San Antonio, told The Texas Tribune on Monday he will cast his ballot for Clinton to send a “clear statement” against Republican nominee Donald Trump’s candidacy.

“I want to make sure that I do everything I can to see that Trump doesn’t get elected,” said Sosa, who has worked for Ronald Reagan and George W. Bush. “I’m doing this because I don’t think he’s a good representative of the Republican Party. It’s not the Republican Party I know.”

Sosa announced in June that he was leaving the GOP over Trump, writing in a San Antonio Express-News op-ed that Trump’s divisive candidacy left him with no choice. Two months later, Sosa joined the campaign of Libertarian nominee Gary Johnson, though Sosa said Monday that move did not amount to a strong enough rebuke of Trump.

“If I vote for Gary Johnson, it’s not enough of a statement,” said Sosa, who had been helping Johnson on a volunteer basis. “I must make a statement that Donald Trump cannot win.”

Sosa’s decision to vote for Clinton comes as the presidential race looks unusually tight in reliably red Texas. She has trailed Trump by 4 points or less in the last three public polls released in the Lone Star State.